Simplify Pawn History Bonus
Passed Non-regression STC:
LLR: 2.98 (-2.94,2.94) <-1.75,0.25>
Total: 122016 W: 31655 L: 31525 D: 58836
Ptnml(0-2): 388, 14317, 31474, 14435, 394
https://tests.stockfishchess.org/tests/view/68f57e66637acd2a11e7221d
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 81348 W: 21016 L: 20858 D: 39474
Ptnml(0-2): 45, 8793, 22841, 8949, 46
https://tests.stockfishchess.org/tests/view/68f9e2d9637acd2a11e72997
closes https://github.com/official-stockfish/Stockfish/pull/6382
Bench: 2370893